1. Field of the Invention
The present invention relates to a keyboard, and more particularly, to a keyboard in which the space between the keys can be adjusted.
2. Description of the Related Art
In general, a keyboard is used as an input device for computers, word processors, and portable information terminals. The keyboard includes a plurality of keys and electric switches corresponding to the keys. When a user presses a key using a finger, an electric switch installed at an inner portion of the key operates to generate a corresponding electric signal. When the key being pressed is released, the key is restored to its initial position and returns to a signal stand-by mode.
Devices adopting a keyboard must be ergonomically designed by considering the structure and operation of a user's fingers. However, since portable devices, such as notebook computers, are manufactured to be easily and conveniently carried by a user, the size of the keyboard must be compact regardless of the size and operation of the hands of the user. Although a compact keyboard is easy to carry, the actual use of the keyboard may be inconvenient since the keys are small and the space between the keys is narrow compared to a nonportable computer. Thus, keyboards for portable devices have been developed to satisfy both convenience in portability and ease of use.
FIG. 1 is a perspective view illustrating a keyboard according to the conventional technology which is disclosed in U.S. Pat. No. 5,141,343.
Referring to the drawing, a housing 2 has a corner/edge member 4 which can be slidably inserted into a stationary corner 3. Likewise, each of the other corner/edge members 6, 7, 8 and 9 are telescopically inserted into at least two other members so that the housing 2 can be extended or retracted. A switch 15 supported by a switch supporting portion 13 is installed under each of keys 11 and 12 and the switch supporting portion 13 is connected to another, adjacent switch supporting portion 13 by a frame 14. The frame 14 has a structure in which the switch supporting portions 13 can approach or retreat from one another. In a keyboard having the above structure, the corner/edge members 4, 6, 7, 8 and 9 extend from the stationary corner portion 3 so that the entire size of the keyboard can be enlarged. Thus, the spaces between the keys 11 and 12 become wider.
However, the above keyboard has several disadvantages. In particular, the structure for enabling the extension and retraction of the keyboard is complex and the key board operation is unreliable. Specifically, since all switch supporting portions 13 arranged latitudinally are connected to each other using the frame 14, the structure of the keyboard becomes complicated and the weight increases. Also, since the corner/edge members 3, 4, 6, 7, 8 and 9 must be separated from each other to operate the keyboard and all the corner/edge members are inserted into other corner/edge members to be carried, such repeated operation causes stress on the frame 14 and the keyboard wears rapidly.